Antifungal Vapour‐phase Activity of a Combination of Allyl Isothiocyanate and Ethyl Isothiocyanate Against Botrytis cinerea and Penicillium expansum Infection on Apples

The potential use of allyl isothiocyanate (AITC) and ethyl isothiocyanate (EITC), singly and in combination, was tested in in vitro and in vivo trials for their effect on Penicillium expansum Link and Botrytis cinerea Persl. infection on apple when used as a fumigant. A 3 : 1 ratio of AITC : EITC was more efficient at reducing in vitro spore germination of P. expansum and B. cinerea than were other combinations or either AITC or EITC alone. The optimized combination showed the lowest EC₅₀ values, at 0.08 and 0.14 μg/ml air, for P. expansum conidial germination and mycelial growth, respectively, and 0.07 and 0.12 μg/ml air for B. cinerea conidial germination and mycelial growth, respectively. In in vivo trials, artificially infected apples were exposed for 4 days to an ITC‐enriched atmosphere. Among the ITCs tested, AITC, EITC and their combinations reduced incidence by more than 85% after 3–4 days of apple incubation at 20°C. Although further studies are necessary to evaluate any detrimental effects on apple quality, the evidence from this study supports the use of fumigation based on ITCs, and in particular a 3 : 1 combination of AITC and EITC, for control of postharvest mildew in apple fruit.     

狐粪青霉挥发性物质的抑菌活性及成分分析

采用对扣法测定狐粪青霉XY180挥发性物质对植物病原真菌的抑制作用,并采用气相色谱—质谱联用技术(GC-MS)分析狐粪青霉挥发性物质的化学成分。结果表明:狐粪青霉挥发物对植物病原真菌的菌丝生长具有一定的抑制作用,从狐粪青霉菌体的乙醚萃取液中共分离到26个组分,鉴定了其中的13个组分。     

Plasma Membrane Damage Contributes to Antifungal Activity of Silicon Against Penicillium digitatum

Putative penicillin-binding proteins (PBPs) were identified in the genome of the Burkholderia cenocepacia strain J2315 based on homology to E. coli PBPs. The three sequences identified as homologs of E. coli PBP1a, BCAL2021, BCAL0274, and BCAM2632, were cloned and expressed as His₆-tagged fusion proteins in E. coli. The fusion proteins were isolated and shown to bind β-lactams, indicating these putative PBPs have penicillin-binding activity.     

Antifungal Activity of Synthetic Scorpion Venom-Derived Peptide Analogues Against Candida albicans

International Journal of Peptide Research and Therapeutics - Fungal infections are becoming a serious problem due to their high morbidity and mortality combined with the rise in drug resistance and...     

Sporicidal Activity of Alkaline Alcoholic Saturated Dialdehyde Solutions

During a search for a sporicidal agent to equal or surpass formaldehyde in activity, a group of saturated dialdehydes ranging from two to six carbons was discovered. These dialdehydes exerted a surprisingly high degree of activity in isopropanol buffered with a carbonate or bicarbonate. Without the proper buffer, practically no activity was observed. A solution of 1% glutaraldehyde, 0.3% NaHCO₃, and 70% isopropanol sterilized stainless-steel penicylinders contaminated with standardized numbers of four spore types in a shorter time than did commercially available 8% formaldehyde solution. Both glyoxal and glutaraldehyde in isopropanol destroyed spores in a relatively short time. Care was taken to eliminate bacteriostasis. Various tests were performed to evaluate accurately experimental and formaldehyde solutions.     

Sporicidal Activity of Sodium Hypochlorite at Subzero Temperatures

Sodium hypochlorite was an excellent disinfectant at low temperatures. With the addition of ethylene glycol to prevent freezing, hypochlorite solutions at low free available chlorine concentrations, were effective against Bacillus subtilis var. niger spores from 0 to -40 C. The effectiveness of this decontaminant was influenced by temperature, pH, and concentration, with pH 7.2 the optimum for decontamination at all temperatures and concentrations.     

The Antifungal Activity of the Penicillium chrysogenum Protein PAF Disrupts Calcium Homeostasis in Neurospora crassa

The antifungal protein PAF from Penicillium chrysogenum exhibits growth-inhibitory activity against a broad range of filamentous fungi. Evidence from this study suggests that disruption of Ca²⁺ signaling/homeostasis plays an important role in the mechanistic basis of PAF as a growth inhibitor. Supplementation of the growth medium with high Ca²⁺ concentrations counteracted PAF toxicity toward PAF-sensitive molds. By using a transgenic Neurospora crassa strain expressing codon-optimized aequorin, PAF was found to cause a significant increase in the resting level of cytosolic free Ca²⁺ ([Ca²⁺]_c). The Ca²⁺ signatures in response to stimulation by mechanical perturbation or hypo-osmotic shock were significantly changed in the presence of PAF. BAPTA [bis-(aminophenoxy)-ethane-N,N,N′,N′-tetraacetic acid], a Ca²⁺ selective chelator, ameliorated the PAF toxicity in growth inhibition assays and counteracted PAF induced perturbation of Ca²⁺ homeostasis. These results indicate that extracellular Ca²⁺ was the major source of these PAF-induced effects. The L-type Ca²⁺ channel blocker diltiazem disrupted Ca²⁺ homeostasis in a similar manner to PAF. Diltiazem in combination with PAF acted additively in enhancing growth inhibition and accentuating the change in Ca²⁺ signatures in response to external stimuli. Notably, both PAF and diltiazem increased the [Ca²⁺]_c resting level. However, experiments with an aequorin-expressing Δcch-1 deletion strain of N. crassa indicated that the L-type Ca²⁺ channel CCH-1 was not responsible for the observed PAF-induced elevation of the [Ca²⁺]_c resting level. This study is the first demonstration of the perturbation of fungal Ca²⁺ homeostasis by an antifungal protein from a filamentous ascomycete and provides important new insights into the mode of action of PAF.The secreted antifungal protein PAF from Penicillium chrysogenum is a small-molecular-mass (6.2 kDa), cationic, and cysteine-rich peptide that inhibits the growth of numerous filamentous fungi (14–16, 21). It belongs to a family of antifungal peptides which show—despite considerable amino acid homology—significant differences in species specificity and modes of action (reviewed in reference 27). Importantly, the primary structures of these antifungals show no similarity to those from higher eukaryotes, e.g., plants, insects, or mammals (see reference 28 for a detailed review on parallels with and differences between PAF and antimicrobial proteins from higher eukaryotes and their mechanisms of action). Apart from the Aspergillus giganteus-derived antifungal protein AFP (19, 45; reviewed in reference 29), PAF is one of the best-studied peptides of this protein family. We have shown that PAF causes rapid hyperpolarization of the plasma membrane at hyphal tips, increased K⁺ efflux, induction of oxidative stress, and apoptotic cell death (21, 25) and that PAF is internalized by hyphae of PAF-sensitive fungi (33). Furthermore, we have shown that PAF interferes with at least two signaling cascades, the protein kinase C/mitogen-activated protein (MAP) kinase and the cyclic AMP (cAMP)/protein kinase A pathways, which play a role in mediating PAF toxicity (5). However, it still has to be elucidated in more detail how these PAF-dependent effects are linked.Recent evidence indicated that the ionic strength of the growth medium interferes with the antifungal activity of PAF (21). It is possible that Ca²⁺ ions may play a major role in influencing protein toxicity in an analogous way to the Ca²⁺-dependent mode of action of antifungal plant defensins. Supplementation of the test medium with low concentrations of CaCl₂ (1 to 5 mM) reversed the antifungal activity of plant defensins (34, 43–44). The defensins RsAFP2 from the seeds of Raphanus sativus and DmAMP1 from the seeds of Dahlia merckii induced K⁺ efflux and Ca²⁺ uptake in Neurospora crassa and caused alkalinization of the growth medium (46). Another seed defensin, MsDef1 from Medicago sativa, was reported to cause Ca²⁺ influx and the inhibition of mammalian L-type Ca²⁺ channels, similar to the Ustilago maydis killer toxin KP4 (13, 40).Ca²⁺ is a universal intracellular second messenger in eukaryotic cells (4, 36). In fungi, there is evidence for Ca²⁺ signaling regulating numerous processes, including spore germination, tip growth, hyphal branching, sporulation, infection structure differentiation, and circadian clocks, as well as responses to osmotic stress, heat shock, mechanical stimuli, oxidative stress, and electrical fields (7, 11, 17, 20, 22, 30–31, 38–39, 41, 49). Ca²⁺ signaling typically involves transient increases in intracellular Ca²⁺ concentrations originating from the extracellular medium and/or mobilization from internal stores (4, 23, 36–37). Little was known about Ca²⁺ dynamics in filamentous fungi until a new method based on the Ca²⁺-sensitive photoprotein aequorin was adapted, allowing routine and easy measurement of intracellular calcium dynamics in these organisms (3, 30).The aim of our study was to investigate the effect of PAF on the level of cytosolic free Ca²⁺ ([Ca²⁺]_c) in the PAF-sensitive target organism N. crassa to characterize its effects on stimulus-specific Ca²⁺ signatures and to define the Ca²⁺ sources responsible for the perturbation of Ca²⁺ homeostasis. By obtaining [Ca²⁺]_c measurements in living cells expressing the bioluminescent Ca²⁺ reporter aequorin, we provide novel insights into the mode of action of this biotechnologically promising antifungal protein.     

Sporicidal Activity of Peracetic Acid and β-Propiolactone at Subzero Temperatures

A method was developed to evaluate and measure the sporicidal activity of peracetic acid (PAA) and β-propiolactone (BPL) at subzero temperatures as low as -40 C. Bacillus subtilis var. niger spores were used as the test organism. Both PAA and BPL were sporicidal at low temperatures, with PAA the more active. The temperature coefficients of the two chemicals are generally low over a range of 20 to -20 C, but increase significantly at temperatures below this. Results showed an initial lag in the PAA death rates that was directly dependent on the temperature. BPL did not show this lag time.     

Temperature-Induced Changes in the Sporicidal Activity and Chemical Properties of Glutaraldehyde

Freshly prepared 2% acid and alkaline glutaraldehyde solutions were stored at 4, 20, and 37 C. At intervals, samples were removed and changes in pH, ultraviolet spectrum, and sporicidal activity (against Bacillus pumilus spores) were recorded. Alkaline solutions stored at 4 C showed little changes in these properties, whereas such solutions stored at 37 C became turbid and showed a decrease in pH, marked changes in ultraviolet spectrum, and an almost complete loss of sporicidal activity. Intermediate results were obtained with alkaline solutions stored at 20 C. In contrast, acid 2% glutaraldehyde solutions (initial pH 3.5) showed comparatively few changes in their properties. Treatment of spores with freshly prepared glutaraldehyde solutions (0.5%) at temperature above 40 C reduced the effect of pH on sporicidal activity.     

Antifungal effect of Penicillium metabolites against some fungi

Microorganisms are increasingly exploited as a source of new biological control agents. Genus Penicillium is a source of novel bioactive molecules which can be used as antifungal agents. The objective of this study was to evaluate the antifungal potential of Penicillium strains. Culture filtrates of two Penicillium species were tested for their antifungal potential by well diffusion assays. Filtrate of Penicillium isolates showed high antifungal effects on mycelial growth of Fusarium oxysporum, Fusarium solani, Macrophomina phaseolina, Aspergillus japonicus var aculeatus and Cladosporium cladosporioides. But Penicillium italicum inhibit the fungal growth from 45 to 68% as compared to Penicillium simplissimum (25–68%). However in case of A. japonicus var aculeatus, Penicillium spp. extracts were equally effective and reduce the colony growth up to 68%. However, P. simplissimum extract was least effective in case of M. phaseolina, where it decreased the colony growth only 25%.     

Effect of Relative Humidity on the Penetrability and Sporicidal Activity of Formaldehyde

The effect of relative humidity (RH) on formaldehyde penetration of paper, glassine, and cotton was determined by the death rate of bacterial spores in glass tubes covered with these materials. The data show that paper is readily penetrated regardless of RH, but the RH greatly affects the penetration rate of glassine and cotton. A comparison was also made of the effect of RH on the penetrability of formaldehyde generated from Formalin and paraformaldehyde. At low RH, all three closures were penetrated more readily by formaldehyde from paraformaldehyde than from Formalin, but no difference in the two was observed at high RH. It is felt that the difference at low RH is primarily due to the condensation of the vaporized Formalin.     

Penicillium Implicatum Causes a Destructive Rot of Pomegranate Fruits

In this study Penicillium implicatum Biourge was found to be the cause of a destructive rot of stored pomegranate (Punica granata) fruits. This species has not previously been reported to cause disease of the fruit. The ability of the strain to decay pomegranates as well as some varieties of apples (Jonagold, Selena and Vanda) under laboratory conditions after inoculation with conidia into the subcutaneous layer of healthy fruits was demonstrated. The fungus was also found on mouldy stamens of pomegranates.     

Antifungal effect and mechanism of garlic oil on Penicillium funiculosum

Garlic oil is a kind of fungicide, but little is known about its antifungal effects and mechanism. In this study, the chemical constituents, antifungal activity, and effects of garlic oil were studied with Penicillium funiculosum as a model strain. Results showed that the minimum fungicidal concentrations (MFCs, v/v) were 0.125 and 0.0313 % in agar medium and broth medium, respectively, suggesting that the garlic oil had a strong antifungal activity. The main ingredients of garlic oil were identified as sulfides, mainly including disulfides (36 %), trisulfides (32 %) and monosulfides (29 %) by gas chromatograph-mass spectrometer (GC/MS), which were estimated as the dominant antifungal factors. The observation results by transmission electron microscope (TEM) and scanning electron microscope (SEM) indicated that garlic oil could firstly penetrate into hyphae cells and even their organelles, and then destroy the cellular structure, finally leading to the leakage of both cytoplasm and macromolecules. Further proteomic analysis displayed garlic oil was able to induce a stimulated or weakened expression of some key proteins for physiological metabolism. Therefore, our study proved that garlic oil can work multiple sites of the hyphae of P. funiculosum to cause their death. The high antifungal effects of garlic oil makes it a broad application prospect in antifungal industries.     

An Antifungal Tetrapeptide from the Culture of Penicillium canescens

A new tetrapeptide D ‐Phe‐L ‐Val‐D ‐Val‐L ‐Tyr ( 1 ), along with three known diketopiperazines and pseurotin A, were isolated from the culture of Penicillium canescens, collected from pollen from beehives, in a screening for new antimicrobial products from unexplored sources. The structure of the tetrapeptide, which exhibits antifungal activity comparable with that of the commercial product benomyl against the soybean phytopathogen Fusarium virguliforme, was determined by spectroscopic (2D‐NMR, and MS and MS/MS) and chemical methods, and the sequence was confirmed by comparison with authentic synthetic isomeric peptides.     

Antifungal Activity of Alkylxylylene-Bis-Isothiuronium Chlorides

Low concentrations of dodecylxylylene-bis-isothiuronium chloride, synthesized from an inexpensive detergent intermediate, inhibited members of 21 genera of fungi.     

Systemic Antifungal Activity of Pyrrolnitrin

The antifungal activity of pyrrolnitrin, previously shown to be effective against superficial infections, was evaluated against experimental systemic mycoses. Pyrrolnitrin was inhibitory in vitro at <0.78 to 100 μg/ml to Candida albicans, Cryptococcus neoformans, Blastomyces dermatitidis, Sporotrichum schenckii, and Histoplasma capsulatum. Pyrrolnitrin activity was reduced about 90% in sera. After multiple subcutaneous doses of pyrrolnitrin at 20 mg/kg, activity was recovered in mouse blood and urine as well as kidney, liver, and brain homogenates. Multiple daily doses (50 mg/kg) of this antibiotic were effective in reducing by 74% the number of viable cells of C. albicans recovered from kidney homogenates. Multiple doses (15 mg/kg) resulted in a 74% reduction in the number of C. neoformans from brain homogenates. Pyrrolnitrin was ineffective in reducing the recovery of B. dermatitidis or H. capsulatum from liver or spleen homogenates of infected mice. When compared with amphotericin B, hamycin, 5-fluorocytosine, and saramycetin, this antibiotic was less effective. This study indicates that pyrrolnitrin would have limited usefulness as a systemic antifungal agent.     

A Rot of Scilla Bulbs caused by Penicillium cyclopium Westling

Summary

The available archaeobotanical evidence from Viking Age sites lying within the boundaries of present day Denmark is summarized and commented upon. The exploitation of both cultivated and wild plant resources is dealt with under the headings - the agrarian economy (crops and weeds), imported plants, collected food plants, brewing, medicinal plants, religion and ritual, wetlands and heaths.     

Antifungal Activity of Substituted Nitrobenzenes and Anilines

Series of 1,3-dihalogeno-5-nitrobenzenes, 3- and 3,5-halogenoanilines, and 2,6-dihalogeno-4-nitroanilines were tested for fungitoxicity against Aspergillus niger, A. oryzae, Trichoderma viride, Myrothecium verrucaria, and Trichophyton mentagrophytes in shaken culture by using Sabouraud dextrose broth enriched with yeast extract as the test medium. 1,3-Dichloro-5-nitrobenzene, 1,3-dibromo-5-nitrobenzene, 3-iodoaniline, 3,5-dichloroaniline, and 3,5-dibromoaniline were found to possess sufficient activity, compared with 8-quinolinol, to warrant further study.     

Synthesis and Antifungal Activity of Curcumol Derivatives

To discover novel and effective antifungal candidates, a series of new curcumol derivatives were designed, synthesized, and evaluated their antifungal activity against five phytopathogenic fungi by the mycelium growth rate method. Derivatives c4 , c22 and c23 exhibited excellent antifungal activity against Phomopsis sp. with EC₅₀ values of 3.06, 3.07, and 3.16 μM, respectively. Specifically, compound c4 exhibited the strongest antifungal activity against Phomopsis sp., which was 44 times that of pyrimethanil (EC₅₀=134.37 μM). The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that compound c4 could cause cell senescence and death of Phomopsis sp. by changing the normal hyphal morphology and disrupting the normal metabolism of hyphal cells. Moreover, compound c4 showed excellent curative effect against Phomopsis sp. on kiwifruit. These findings confirmed that compound c4 has great potential as a potent antifungal agent.     

Mechanism of Sporicidal Activity for the Synergistic Combination of Peracetic Acid and Hydrogen Peroxide

There is still great interest in controlling bacterial endospores. The use of chemical disinfectants and, notably, oxidizing agents to sterilize medical devices is increasing. With this in mind, hydrogen peroxide (H₂O₂) and peracetic acid (PAA) have been used in combination, but until now there has been no explanation for the observed increase in sporicidal activity. This study provides information on the mechanism of synergistic interaction of PAA and H₂O₂ against bacterial spores. We performed investigations of the efficacies of different combinations, including pretreatments with the two oxidizers, against wild-type spores and a range of spore mutants deficient in the spore coat or small acid-soluble spore proteins. The concentrations of the two biocides were also measured in the reaction vessels, enabling the assessment of any shift from H₂O₂ to PAA formation. This study confirmed the synergistic activity of the combination of H₂O₂ and PAA. However, we observed that the sporicidal activity of the combination is largely due to PAA and not H₂O₂. Furthermore, we observed that the synergistic combination was based on H₂O₂ compromising the spore coat, which was the main spore resistance factor, likely allowing better penetration of PAA and resulting in the increased sporicidal activity.